Shiftable fifth wheel mounting for axle loading adjustment



Jan. 7, 1958 c. M. SENCENICH 2,819,096

- SHIFTABLE FIFTH WHEEL moummc FOR AXLE LOADING ADJUSTMENT 2Sheets-Sheet 1 Filed Oct. 30. 195.6

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a 1 5 c. M. SENCENICH 2,819,096

SHIFTABLE FIFTH WHEEL MOUNTING FOR AXLE LOADING ADJUSTMENT Filed Oct.30, 1956 2 Sheets-Sheet 2 IIII/Il/I/I/IIIIIIII/I/lIIIIIII/II/I/I/I/IIIl/II/l/ MA m2 1 19'. 4 E 45 W/////////////////4 INVENTOR/1/l//////////////////////Al E9! 5 M W iz w i United States SHIFTAELEFIFTH WHEEL MOUNTING FOR AXLE LOADING ADJUSTMENT Carl M. Sencenich,Kansas City, Kans. Application October 30, 1956, Serial No. 619,214 2Claims. (Cl. 280-497) This invention relates to new and usefulimprovements in fifth wheel devices such as are commonly used in thetrucking industry to connect the tractor and trailer units of commercialtrucks, and relates more specifically to a new and novel means formounting such fifth wheel assemblies on the tractor unit of such truckcombinations.

Fifth wheel operation is of course generally well understood, the devicebeing operable to provide a universal front connection of a trailer,which is customarily provided only with one or more rear axles, to therearward portion of a tractor, which is customarily provided with bothfront and rear axles. The principal object of the present invention isthe provision of means whereby the fifth wheel connection may be shiftedforwardly or rearwardly at will with respect to the tractor unit. Thisadjustment is of the greatest assistance in meeting and complying withthe truck-loading laws enacted by various governmental agencies for theprotection of public roads and safety.

These laws fall generally into three categories: Firstly, limitations onthe overall length of the tractor-trailer combination. Secondly,limitations on the load supported by each axle. Thirdly, limitations onthe load per axle wherein the load limit is based on the distancebetween the rear axle of the tractor and the rear axle of the trailer.The latter are often called bridge laws. The adjustment i propose willtend to permit conformity with all of these laws. Shifting the point ofsupport forwardly or rearwardly with respect to the tractor will notonly change the overall length of the tractor-trailer combination andthe distance between the tractor and trailer axles, but will also permitproportioning of the trailer weight supported by the fifth wheel betweenthe front and rear tractor axles. F or example, shifting the fifth wheelforwardly and closer to the front tractor axle will impose a greaterproportion of the weight to said front axle, and a correspondinglysmaller proportion on the rear tractor axle.

Other objects of the invention are the provision of a mounting of thecharacter described which is simple and economical in structure,dependable and eflicient in operation, which is not likely to get out oforder, wherein the latching means which secures the mounting at any desired position is easily releasable by manual force, and which isvirtually universally adaptable to many types of pre-existing trucks andfifth wheel mechanisms.

With these objects in view, as Well as other objects which will appearin the course of the specification, reference will be had to thedrawing, wherein:

Fig. l is a fragmentary side elevational view of a tractor and trailercombination, showing the fifth wheel con- .ection therehetween, andincluding a fifth wheel mounting embodying the present invention,

Fig. 2 is an enlarged fragmentary sectional view taken on line 11-11 ofFig. 1, with parts broken away,

Fig. 3 is an enlarged fragmentary sectional view taken on line HIIII ofFig. 2, with parts broken away,

Fig. 4 is a fragmentary sectional view taken on line iV-IV of Fig. 3,

Zhlfhh fi Patented Jan. 7, 1958 Fig. 5 is an enlarged fragmentarysectional view taken on line V-V of Fig. 3, and

Fig. 6 is an enlarged sectional view taken on line VI VI of Fig. 5.

Like reference numerals apply to similar parts throughout the severalviews, and the numeral 2 applies generally to a truck tractor unitincluding a frame 4 consisting of a pair of horizontal, parallel, spacedapart channels 6 connected at various points along their length by crossbars 8. The usual cab it) is mounted on the forward portion of frame 2,and it will be understood that the forward end of the frame is supportedby the usual front steerable wheels, not shown. The rearward end of thetractor frame is supported by ground-engaging wheels 12 carried by rearaxle 14. The truck trailer 16 includes a trailer body 18 which it willbe understood extends substantially rearwardly from the tractor and issupported adjacent its rearward end by the usual rear axle and wheels,not shown.

The trailer body is connected adjacent its forward end to the tractorframe by means of a fifth wheel mechanism 24) including a generallyovate pressure plate 22 having a planar upper surface and havingdownwardly and rearwardly inclined tongues 24. Said pressure plate isprovided with a slot 26 opening through the rearward edge of the plateand tapers forwardly to the central portion of the plate. The plate issupported by bearings 28 for pivotal movement on a horizontal axle 3dtransverse to the line of travel of the truck, said axle being supportedin bearings 32 which are formed integrally with standards 34. Saidstandards are each provided with an enlarged foot 35. Said feet areprovided with securing bolts 33 which in the common installation serveto aifix feet 35 rigidly to the tractor frame, but which according to myinvention affix said feet to a movable carriage, as will be described.

Trailer body 18 has a skid plate 40 attached to the bottom thereof andextending rearwardly from the for ward end thereof. A short, heavykingpin 42 is fixed in and depends from said skid plate. Thus when therearward end of the tractor is backed under the forward end of thetrailer, skid plate 4t contacts and slides over pressure plate 22,kingpin 42 entering and passing forwardly through slot 26 of saidpressure plate. When the kingpin reaches the forward end of the slot, itis automatically locked therein by a mechanism including jaws 4 4, saidmechanism being carried on the lower side of pressure plate 22, but notbeing detailed here, since the structure thereof forms no part of thepresent invention.

According to my invention, the fifth wheel feet 36 are mounted on acarriage 46 mounted movably on a pair of tracks or rails d8 aflixed totractor frame 2. Each of tracks ift comprises a flat steel platedisposed above and parallel to one of frame channels 6, and is afiixedto said channel by an l-bearn 5% which is: coextensive therewith, thebottom flange of the I-beam being welded to channel 6, and the upperflange of the I-beam being welded to the track. Preferably the tracksextend both forwardly and rearwardly from the vertical plane of reartractor axle id.

Carriage :6 comprises a pair of tZ-shaped channels carried respectivelyon the two tracks 48, the central web of said channel being planar andresting in sliding contact with the track, and the edge portions of saidchannel having a slidin hook engagement with the edges of the track,clearly shown in Fig. 3. The carriage channels are rigidly joined attheir rearward ends by a cross bar 54 (see Fig. 2), and at their forwardends by a cross bar as formed of plate stock. It will be understood thatfeet Elti of the fifth wheel bearings 32 are secured by bolts 38 tocarriage channels 525. Said channels may be bored specially to receivethe bolts for b ll any particular fifth wheel, or they may have aplurality of holes bored therein so as to be adapted to receive varioustypes of fifth wheel feet. It is quite important that the carriagechannels :52, be of substantial length as compared to their width, andthat they have fulllength engagement with the tracks, in order toprevent possible binding or cramping thereof on the tracks under theextreme loading conditions involved.

The carriage is releasably held at any of a series of positions alongtracks :8 by a pair of detent pins carried by cross bar se andengageablc respectively in tracks As best shown in Fig. 5, each of saidpins is disposed vertically and carried slidably in a cylindrical guide60 integrally connected to cross bar 56. Said pin extends downwardlythrough a hole 62 formed in carriage channel and then selectivelythrough any of a series of longitudinally spaced apart holes '54 formedin track d8. Said detent pin extends upwardly from guide 60 into arectangular housing at; which essentially comprises a forwardly openingchannel welded to cross bar 56, with the forward portion thereof closedby a plate '70 welded thereto. Carried for vertical sliding movement insaid housing is a substantially rectilinear block 72 which is secured tothe upper end of detent pin 58 by screw '74. The upper end of housing 66is closed by a removable cap "755, and a compression spring '73 retainedbetween said cap and said block serves to urge the detent pin downwardlyto its operative position.

The detent pins may be elevated to an inoperative position above tracks40 by a mechanism including an operating bar 50 which extendshorizontally between the two detcnt housings 6e, and through windowsformed in the opposite side Walls of each of said housings. Saidoperating bar is disposed forwardly of the detent pins, but beneath theforward portions of the blocks 72, and is supported throughout itslength by a rearwardly extending ledge 34- which is carried at the upperedge of an upstanding wall 86 disposed along the forward edge of crossbar 5-6. Said operating bar is longitudinally slidable along said ledge.It is braced against lateral movement by upstanding walls 38 and 90affixed to ledge 84 respectively along the forward and rearward edgesthereof.

A pair of wedges 92 are welded to the upper edge of bar 80, respectivelyadjacent each of the detent housings d. The inclined upper face of eachof said wedges rests in engagement with'a correspondingly inclined wedgefollower surface 94 of the associated detent block 72. It will beapparent that if bar 30 is moved to the right as viewed in Figs. 3 and4, wedges d2 will elevate blocks 72 above tracks 4-8, so that the entirecarriage 46 may be shifted forwardly or rearwardly along said tracks.The operating bar is moved by means of a bell crank lever 96 pivoted at98 to a boss 100 formed integrally with a cross bar 56. Said lever has along arm 102 and a shorter arm A link 1% is connected at one end to themovable end of lever arm 104 by pivot lltlil, and is connected at itsopposite end to operating bar 80 by pivot 110.

Pulling lever arm 102 forwardly will urge bar 80 to the right as viewedin Figs. 3 and 4. The mechanical advantage of the lever itself, and thatof the Wedges 92, provides a tremendous lifting force on the detent pins58, so that they may be disengaged even through there may be a greatload on the fifth wheel connection. The tractor may then be movedforwardly or rearwardly to cause relative movement of carriage 46 alongtracks 48, for the purpose of changing the overall length, axle spacing,or load distribution to the axles, as previously described. When thecarriage is disposed approximately at the position desired, lever arm102 is returned rearwardly to its normal position, which moves wedges 92to the left, and frees blocks '72 therefrom. When detent pins 58 passover the next holes 64- of the tracks, they will be urged downwardlyinto said holes by springs 73.

For safety, in order to prevent possible separation of tractor andtrailer in the event the detent mechanism should fail, there is providedan upstanding block 112 welded or otherwise secured to the upper surfaceof each of tracks at the rearward ends thereof, and a transverse crossbar 11 welded to the upper surface of said tracks at the forward endsthereof. These blocks and cross bar prevent the carriage from travellingoil of either end of the tracks.

While I. have shown and described a specific embodirnent of myinvention, it will be apparent that numerous minor changes of structureand operation could be made without departing from the spirit of theinvention as defined by the scope of the appended claims.

What I claim as new and desire to protect by Letters Patent is:

l. A fifth wheel mounting for a truck tractor having a frame, saidmounting comprising a track adaptedto be ailixed to said tractor frameso as to extend forwardly and rearwardly, a carriage mounted on saidtrack for movement therealong, said carriage being adapted to carry afifth wheel assembly mounted thereon and movable therewith, a detent pincarried by said carriage for movement relative to said carriagetransverse to the direction of movement of said carriage on said track,said detent pin being selectively engageable in any of a series ofapertures formed tl erefor in said track, resilient means carried bysaid carriage and urging said detent pin to an operative positionengaging said track, a wedge member carried by said carriage formovement in a direction transverse to the movement of said detent pin,said wedge engaging a cooperating wedge surface rigidly associated withsaid detent pin, and manual means operable to move said wedge whereby toretract said pin to an inoperative position, against the pressure ofsaid resilient means.

2. A mounting as recited in claim 1 wherein said track comprises a pairof spaced apart apertured rails and said carriage includes a pair ofchannel members rigidly connected together and respectively engagingsaid rails for sliding movement therealong, and wherein each of saidchannels is provided with a detent pin as recited and operable to engageselectively the apertures of the associated rail, and with the additionof an operating member carried by said carriage for movement transverseto said detent pins, said operating wedge for each of said pins bothbeing mounted on said operating member.

References (Cited in the file of this patent UNITED STATES PATENTS Re.23,704 De Lay Sept. 1, 1953 2,317,508 Zoder Apr. 27, 1943 2,713,500Flynn July 19, 1955 2,750,207 Greenway .a June 12, 1956 2,755,104Braunberger July 17, 1956

